1. Field of the Invention
This invention relates to a satellite broadcasting tuner.
2. Description of the Prior Art
As a pay system is employed for reception of satellite broadcasting, broadcasting of a video signal in a scrambled condition is employed by some satellite broadcasting channels. If broadcasting in a scrambled condition is employed by a channel, then mere reception of broadcasting of the channel by way of a satellite broadcasting tuner will not allow a video image to be displayed on a monitor screen.
In order to permit broadcasting which involves such special signal processing to be enjoyed, a receiver system must necessarily have such construction as shown in FIG. 3. In particular, referring to FIG. 3, a receiver system must be constructed not only such that a video signal and left (L) and right (R) aural signals demodulated by and outputted from a satellite broadcasting tuner 1 are supplied directly to a monitor apparatus 2 as in a conventional system, but also such that, in order to cope with broadcasting which involves scrambling processing, a signal demodulated by the satellite broadcasting tuner 1 is supplied once to a decoder unit or de-scrambler 3 to de-scramble the same and output signals of the de-scrambler 3 (video signal and L and R aural signals) are supplied to the monitor apparatus 2. In short, broadcasting of a channel which involves scrambling processing cannot be enjoyed without such de-scrambler 3, and accordingly, a receiver system requires two signal input systems to a monitor apparatus 2.
It is to be noted that reference numeral 4 in FIG. 3 denotes a satellite broadcasting antenna, and 5 a satellite broadcasting converter.
By the way, where a receiver system is constructed to cope with scrambled broadcasting in this manner, if scrambled broadcasting is performed with a particular channel, then the monitor apparatus 2 must have two input modes or input terminals for reception of satellite broadcasting of the particular channel and for reception of satellite broadcasting of any other channel which does not involve scrambling processing.
In short, for ordinary satellite broadcasting, a circuit system of the monitor apparatus 2 must be connected so that a signal may be supplied thereto by way of an external input terminal section T.sub.1, but for scrambled satellite broadcasting, the circuit system must be connected so that a signal may be supplied by way of the other external input terminal section T.sub.2.
Accordingly, when it is tried to change over a receiving channel, for example, from an ordinary satellite broadcasting channel to the scrambled satellite broadcasting channel, an operation of changing over the input mode of the monitor apparatus 2 must be performed together with a channel changing over operation.
Consequently, such problem takes place that a satellite broadcasting channel selecting operation is so complicated that a channel changing over operation cannot be performed particularly by a user who is unfamiliar with such apparatus or does not recognize an input mode of the monitor apparatus 2.